Mass, Balance and Loading
Mass terms, arms, moments, centre of gravity, load sheets, envelopes and structural or controllability consequences.
How to prepare for UK CAA PPL theory
Work from the training-organisation recommendation and selected aircraft category, map study to the current CAA learning objectives, and use the live booking confirmation for paper-specific logistics.
Core concepts
Concept 1
Mass, datum, arm and moment combine to locate the loaded centre of gravity.
Exam cue: Use one datum, one sign convention and compatible units.
Concept 2
Maximum mass and centre-of-gravity limits protect structure, performance, stability and controllability.
Exam cue: Check both mass and centre of gravity at the limiting flight conditions.
Concept 3
Loading changes during flight when fuel is used or occupants and baggage differ from the plan.
Exam cue: Plot or calculate the result against the correct envelope.
Risk pitfalls and guardrails
Checking take-off mass but not landing mass.
Guardrail: Do not blend aeroplane and helicopter objectives or treat the aggregate 601-item study allocation as an official CAA question total.
Using planned rather than actual loading data.
Guardrail: Do not blend aeroplane and helicopter objectives or treat the aggregate 601-item study allocation as an official CAA question total.
Treating an in-envelope mass as proof the centre of gravity is acceptable.
Guardrail: Do not blend aeroplane and helicopter objectives or treat the aggregate 601-item study allocation as an official CAA question total.
Memory anchors
Moment
Moment equals mass multiplied by arm.
CG
Centre of gravity is total moment divided by total mass.
Two Limits
Mass and centre of gravity must both remain within limits.
Fuel Change
Fuel burn can change both mass and centre of gravity.
Document
Use current aircraft loading data and the applicable envelope.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
A 75 kg passenger sits 2.4 m aft of the datum. What is the moment?
A 20 kg bag is at an arm of 3.1 m. What moment does it add?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
What is Pass Harbor?
Completely free exam prep for 247 UK exams.
- Practice questions
- Flashcards
- Study guides
- Mock exams
- No registration
- No paywall
- Start instantly
“No more expensive exam prep. Quality study tools should be accessible to everyone.”